Dipole sonic logging in a fluid-filled borehole has been provided with DSI and Sonic Scanner, which are tools manufactured by the applicant. The tool diameter for these tools is 3⅝″. For DSI, the acquisition electronics are located in an air section, which is away from the hydrophone sensors. In the case of Sonic Scanner, the amplifier and analog digital (A/D) converter are located closely to the sensors. To enable such a configuration, the structure in the receiver section and the electronics are contained in an outer sleeve, and non-conductive fluid is filled in the outer sleeve. This arrangement complicates the system because of the need for oil volume compensation under downhole conditions, and system maintenance is difficult.